The endoscopic guides (or “guidewire” in technical jargon) are used in the field to position and act, in fact, as a guide, in particular for a catheter, which is usually mounted sliding thereon; to this end, the catheter is provided with an operating channel in which the guide itself is placed in an assembled condition.
In the prior art, depending on the applications for which they are intended, various types of endoscopic guides are known.
A type of endoscopic guide provides an anchoring head which allows the guide to remain in place and acts as a support for the operations of the catheter or endoscope.
In some embodiments, for this purpose, the guides are provided with an inflatable balloon which, once introduced into the lumen of the organ and positioned, is inflated with air until it interferes with the walls of the lumen, thus remaining locked in place.
Although these guides with expandable anchoring head are used, they do however have some drawbacks.
In fact, these guides are “passive” in placing, i.e. they must be positioned manually by the medical operator and can be locked in place only when they are exactly at the desired point: in fact, if a small adaptation of their position is necessary, it would be necessary to deflate the balloon, position the head again and proceed with a new locking in place.
These operations require some time, which leads to additional discomfort for the patient.
Another limitation of some of these solutions is related to the fact that the lumen in which the guide head is placed is occluded: in the case of inflatable balloons, in particular, the occlusion is complete, while in the case of metal cages the occlusion is only partial, but only small passage areas between the segments of the cage remain available.
Moreover, such anchoring heads are difficult to be used in certain endoscopy fields, such as in the case of colonoscopy, due to the anatomical conformation of the organ in which the guide is introduced. In the colon, for example, the lumen diameter can range from 2-3 cm up to 6-8 cm in relation to the considered segment and to the presence or absence of pathological conditions or anatomical anomalies. This would imply the need for even very voluminous balloons.
Moreover, the anchoring through the balloons is obtained through the friction which is generated between the balloon and the surface of the organ mucosa. This implies that in order to obtain a more stable anchorage it is necessary to increase the pressure on the wall of the bowel, thereby extending the balloon further. However, this operation could result in excessive extension of the bowel, with the risk of causing pain or even tearing the tissue. Moreover, sometimes the bowel, especially in the elderly or in certain pathological conditions, may be dilated and flaccid to such an extent that it does not offer resistance to the balloon expansion. In this condition, the distension of the balloon can not only be risky, but is also ineffective.
However, obtaining a steady and stable anchoring is essential to ensure that the guide can also work for colonoscopes and in general endoscopes.
The colonoscope technique in particular requires special precautions for the introduction of the colonoscope to the terminal point of the colon, since the colon, in addition to having a twisted pattern, has flaccid walls whereby loops are formed which prevent the advance of the colonoscope tip and stretch the walls of the colon, thus causing the onset of pain and the risk of tearing the bowel: in these cases, the doctor must maneuver the instrument in an appropriate manner so as to rectify as much as possible the path and be able to proceed with the introduction of the colonoscope to the terminal point.
It should also be considered that the main difference between a colonoscope and a standard catheter is mass. As the mass of the catheter or the endoscope increases, a guide with higher stiffness is required. The rigidity of the guide derives mainly from two factors: the material it is made of and the force with which it is put in traction; the greater the pulling force, the larger the catheter mass. In order for the pulling force to be greater, it is necessary to achieve an anchoring as firm as possible.
The guides currently used in endoscopy cannot be constructed with particularly rigid material, as this could damage the bowel with the rigid tip.
In the case of anchoring with an inflatable balloon, when traction is exerted on the outer end of the guide during the above maneuvers, a traction not only of the guide is determined, but also of the balloon, of the bowel mucosa where the balloon is anchored and thus of the whole bowel and its ligaments. This sequence of events could lead to the onset of pain due to the traction of the visceral ligaments and damage to the mucosa. With these instruments, anchoring could also be ineffective.
In this regard, it should be noted that in the guides with inflatable balloon, the outer end of the guide is connected to an insufflator which regulates the pressure of the gas inside the balloon; this means that the outer end of the guide is not free, but engaged by the insufflator.
Even if, in principle, one could think of changing this anchoring area, there remains the limitation relating to the necessary presence of the insufflator, which has a certain cost and an additional encumbrance of the equipment, in addition to the necessary maintenance. Continuous control of the insufflation pressure is also required during use.
Another limitation of these solutions relates to the fact that an insufflator is not always available in every endoscopic room.
A common limitation of the known solutions of the prior art is also that it is not possible to remove the endoscope in use from the guide and replace it with another endoscope, keeping the guide in place; this is due to the fact that along the guide wire there are usually control devices which could hinder the extraction and therefore the replacement.
Yet another limitation of such solutions is related to the fact that it is generally appropriate for the dimensions of the anchoring or positioning head to be as small as possible, so as to be able to be easily introduced and maneuvered.
It should then be considered that, especially when the endoscopy consists of a colonoscopy, another limitation is related to locating the lesion (e.g. tumor, polyp or the like) by the operator. Locating is in fact of primary importance, for example to indicate to the surgeon in which segment of the colon there is a lesion which has been identified by the endoscopist during the colonoscopy. For example, it may happen that the endoscopist operator says that a polyp is in the descending colon, when it is in the sigmoid or in the transverse colon.
This happens because within the colon there are few points of reference, which induces even gross locating errors.
It is an object of the invention to provide an endoscopic guide for catheters or endoscopes which solves one or more of the technical problems described above. In this context, it is an object of the present invention to provide an endoscopic guide which is able to ensure a solid and less traumatic anchoring, in particular for use in colonoscopy.
It is another object of the invention to provide an endoscopic guide which allows to exert a significant pulling force on the guide itself.
It is a further object of the invention to provide an endoscopic guide which can also be used with large mass colonoscopes.
It is another object of the invention to provide an endoscopic guide which allows at least small movements of the anchoring head to be carried out when it is in the locked position, so as to avoid unnecessary activation/deactivation maneuvers.
It is another object of the invention to provide an endoscopic guide which allows the endoscope to be replaced while keeping the guide locked in place in the organ.
It is another object of the invention to provide an endoscopic guide which is relatively quick to be operated.
It is yet another object of the invention to provide an endoscopic guide which is relatively cost-effective and simple to be implemented.
It is another object of the invention to provide an endoscopic guide which is relatively safe even in case of malfunctions.
It is a further object of the invention to provide an endoscopic guide which allows to precisely locate possible lesions (e.g. tumors, polyps or the like), especially when the invention is used for a colonoscopy.